Method and apparatus for correcting heliostat

ABSTRACT

Provided are an adjusting method and an adjusting apparatus for adjusting a heliostat on site while actually measuring that a mirror surface of the heliostat and a mirror surface of a center reflector are exactly facing each other. The adjusting apparatus is provided with an irradiation device  3  which irradiates an upper focal point p of a center reflector  30  and a heliostat  20  with laser beams L 1  and L 2,  respectively. The elevation angle and/or the turning angle of the heliostat  20  are adjusted so that the reflected light L 4  of the laser beam applied on the heliostat  20  forms the same axial line as the laser beam L 1  applied on the upper focal point p of the center reflector  30.

TECHNICAL FIELD

The present invention relates to a heat collecting device which collects solar heat by means of multiple heliostats, and more particularly relates to a method and an apparatus for correcting a heliostat which reflects solar heat.

BACKGROUND ART

Recently, due to soaring prices of fossil fuels and for the protection of global environment, research and development on clean energy not derived from fossil fuels have been actively carried out. As such clean energy, power generation utilizing wind power or solar heat has been started to be implemented.

In particular, much attention has been paid to a solar thermal power generation system in which a heat medium is heated by collecting solar heat so as to generate steam with the heat medium as a thermal source for driving a steam turbine, thereby generating electricity. This is because the solar thermal power generation system is capable of being operated using a power generation facility similar to that for conventional thermal power generation while being capable of achieving high output.

As such a solar thermal power generation system capable of achieving high output, a solar thermal power tower system and a beam-down system for solar thermal power generation have been known (refer to the Patent Document 1 and the Non-patent Document 1, for example).

In the solar thermal power tower system described above, multiple heliostats having planar reflecting mirrors are arranged around a tower having a heater made of a heat medium provided in an upper part thereof, and the multiple planar reflecting mirrors are adjusted so that solar heat can be concentrated into the heater.

In the beam-down system for solar thermal power generation described above, multiple heliostats having planar reflecting mirrors are arranged around a tower having a hemispherical center reflector provided in an upper part thereof, and a heater made of a heating medium provided below the reflector plate to collect solar heat reflected from the multiple reflecting mirrors.

Further, each heliostat is provided with a tracking device sensing the movement of the sun, and is controlled so as to irradiate the heater or the center reflector with solar heat.

Meanwhile, the adjustment of the heliostat described above has been carried out as follows: first, an orientation angle and an elevation angle are roughly adjusted on the basis of calculated values obtained from numerical values specified in design drawings, and then the orientation angle and the elevation angle are further adjusted on the basis of calculated values obtained from numerical values derived from measurement of the actually-used heliostat.

PRIOR ART DOCUMENT Patent Document

Patent Document 1: Japanese patent application Kokai publication No. 2005-106432

Non-Patent Document

Non-patent Document 1: Solar Energy, Volume 62, Number 2, February 1998, pp. 121-129(9)

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

In the case of the solar thermal power tower system and the beam-down system for solar thermal power generation described above, a variation and/or a deviation in a direction of the solar heat irradiation occur due to measurement errors, since the orientation angle and the elevation angle of the heliostat are adjusted on the basis of the calculated values derived from design drawings and of measurement as described above.

In this regard, it may also seem plausible that multiple workers track the sunlight position while looking in a telescope for the purpose of improving the adjustment accuracy of the orientation angle and the elevation angle of a heliostat. However, such an operation is not practical as the checking has to be carried out whenever the heliostat is adjusted, thus involving a large amount of time, effort, and labor costs.

Furthermore, solar thermal power tower systems and beam-down systems for solar thermal power generation are built in desert areas and the like in Middle Eastern countries and the like, where the difference in temperature between day and night is large and the solar thermal power tower systems and the beam-down systems for solar thermal power generation are exposed to gale force wind. Therefore, there has been a problem that large mirror plates (facets) disposed on the heliostat are dislocated. That is, there has been a problem that the heat collecting efficiency gradually decreases from the time when the power generation systems are first installed.

Focusing on such problems having arisen in the past, the present invention has an object to provide a correcting method and a correcting apparatus, the method and the apparatus being capable of adjusting a heliostat on site while actually measuring that an optical axis of facets disposed on the heliostat and an optical axis of an upper focus of the center reflector are in alignment.

Means for Solving the Problems

A method for correcting a heliostat according to the present invention is configured as follows so as to achieve the above-described object.

1) The method for correcting a heliostat, in a heat collecting device including: a center reflector provided in an upper portion thereof; a heat receiving part provided in a lower part thereof; and a plurality of heliostats arranged around the center reflector, is characterized by comprising the steps of: providing an irradiation device irradiating an upper focal point of the center reflector and the heliostat with laser beams, respectively; and adjusting an elevation angle and/or a turning angle of the heliostat so that a reflected light of the laser beam applied on the heliostat forms a same axial line as the laser beam applied on the upper focal point of the center reflector.

An apparatus for correcting a heliostat according to the present invention is configured as follows.

2) The apparatus for correcting a heliostat, in a heat collecting device including: a center reflector provided in an upper portion thereof; a heat receiving part provided in a lower part thereof; and a plurality of heliostats arranged around the center reflector, is characterized by comprising an irradiation device irradiating the center reflector and the heliostat with laser beams, respectively, the irradiation device being provided on a light path connecting an upper focal point of the center reflector and the heliostat to each other.

3) The apparatus for correcting a heliostat is characterized by comprising: a light receiving device detecting a reflection laser beam reflected from the heliostat, the light receiving device being provided in the vicinity of the laser irradiation device side-by-side therewith; and an adjusting device which turns and elevates the irradiation device and the light receiving device.

4) The apparatus for correcting a heliostat is characterized in that the laser irradiation device is attached to and detached from the correcting apparatus by attachment and detachment means, and is driven by a storage battery.

5) The apparatus for correcting a heliostat is characterized in that the laser irradiation device irradiates the upper focal point of the center reflector with a laser beam having a wavelength in a range of 500 nanometers to 590 nanometers.

6) The apparatus for correcting a heliostat is characterized in that the light receiving device is a sun tracking device.

Effects of the Invention

The irradiation device which irradiates an upper focal point of the center reflector and the heliostat with laser beams, respectively, is provided. The elevation angle and/or the turning angle of the heliostat is adjusted so that a reflected light of the laser beam applied on the heliostat forms the same axial line with the laser beam applied on the upper focal point of the center reflector. Therefore, correction at an extremely high accuracy can be achieved in comparison with adjusting methods based on measurement and adjusting methods in which workers carry out adjustment by looking in a telescope.

Further, since the laser irradiation device can be attached and detached, multiple heliostats can be corrected sequentially with the single irradiation device. Therefore, installation costs of the irradiation device can be reduced.

Furthermore, since the correction operation can be carried out even by one person, the efficiency can be improved significantly compared to an adjustment operation carried out by multiple persons upon spending time and effort.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration diagram of a solar thermal power generation system.

FIG. 2 is a schematic configuration diagram of a correcting apparatus according to the present invention.

FIG. 3 is a schematic drawing of a laser irradiation device.

FIG. 4 is a drawing showing a method for correcting a heliostat using the correcting apparatus according to the present invention.

FIG. 5A shows the relation between movement of a facet disposed on the heliostat and the correcting apparatus during correction.

FIG. 5B shows the relation between movement of the facet disposed on the heliostat and the correcting apparatus after completion of the correction.

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described on the basis of the attached drawings.

FIG. 1 is a schematic configuration diagram of a solar thermal power generation system A in which a correcting apparatus according to the present invention is used. As shown in FIG. 1, the solar thermal power generation system A is provided with a disc-shaped center reflector 30 supported on an upper part of a supporting column 31 and a heliostat 20 arranged around the center reflector 30. Beneath the center reflector 30, a receiver 33 which collects solar heat is provided. A power generation system (not shown in the drawing), such as a steam turbine using molten salt heated by the receiver 33 as a thermal source, is also provided.

The heliostat 20 described above has multiple facets 21 arranged therein in three rows, and the facets are linked together via a link 24A of an elevating device 24 so that the elevation angles of the respective facets can be adjusted. Also, the turning angle of the heliostat 20 can be adjusted with a turning device 25.

Next, a correcting apparatus according to the present invention will be described.

As shown in FIG. 2, a correcting apparatus 1 includes: an irradiation device 2 on which laser oscillators 2A and 2B are formed in such a manner as to respectively extend linearly from both sides of a flange-shaped attachment 2F, and a light receiving device 3 which is disposed in the vicinity of the irradiation device 2 to detect a reflected light L4 of a laser beam. Further, the irradiation device 2 and a light receiving device 3 are fixed to a fixing plate 4 so that respective axial lines can be parallel to each other.

The fixing plate 4 is pivoted on two arm parts 8 erected on a bed plate 8D, and can be fixed at a specific elevation angle by placing a positioning bolt 8A through a circular bolt hole. Further, the bed plate 8D is fixed to a plate-shaped base part 6 with a bolt 6A, and a bolt hole for the bolt 6A also has a circular shape so that the bed plate 8D can be fixed rotatably. In addition, the bed plate 8D can be subjected to fine adjustment with a slow-motion stage 9 provided below the base part 6.

Furthermore, a horizontal adjusting device 13 and a vertical adjusting device 12 are provided. A member, such as a micrometer head, which is capable of carrying out fine adjustment is used for these adjusting devices.

As shown in FIG. 3, the irradiation device 2 is provided with the laser oscillators 2A and 2B respectively provided on both sides of a flange-shaped attachment 2F so that laser beams L1 and L2 respectively irradiated from the laser oscillators 2A and 2B can come on a same axial line. A side surface of the attachment part 2F is formed on a reference plane f so that the irradiation device 2 can be parallel to the light receiver 3 when attached to the fixing plate 4.

Further, the light receiver 3 serves as a sun tracking sensor. When normal power generation is carried out, the turning device 25 and the elevating device 24 of the heliostat 20 are controlled so that a reflected light r2 from the heliostat 20 can be the maximum value.

Next, a correcting method for the heliostat 20 using the correcting apparatus 1 thus configured will be described.

FIG. 4 is a schematic drawing showing a state in which the heliostat 20 is being corrected by adjusting the orientation angle and the elevation angle of the facet 21 disposed on the heliostat 20.

The correcting apparatus 1 according to the present invention is arranged on a light path c connecting the center reflector 30 and the heliostat 20 to each other, and is disposed in the vicinity of the facet 21 disposed on the heliostat 20.

The correcting apparatus 1 is provided in the vicinity of the facet 21. This is because the low height of the light path c at the position from ground ensures a stable operation to be carried out on a work table as small as a trolley. Further, the correcting apparatus 1 is provided in such a position because the position is suitable to adjust the elevation angle and the orientation angle of the heliostat 20.

For correction of the heliostat 20, first, the irradiation device 2 is fixed to the fixing plate 4, to which the light receiver 3 serving as a sun tacking device is fixed, to obtain the correcting apparatus 1. Next, the laser beam L1 is irradiated from the correcting apparatus 1 toward an upper focal point p of the center reflector 30.

Since the distance between the upper focal point p and the heliostat 20 varies in a range of tens of meters to hundreds of meters depending on the scale of the solar thermal power generation system, a laser beam having a wavelength which is easily visually recognizable even from far is used as the laser beam L1 being irradiated.

The wavelength of the beam light is preferably in a range of 500 nanometers to 590 nanometers. In the present embodiment, a green light having a wavelength in the vicinity of 555 nanometers (532 nanometers), which human eyes can perceive most strongly, is used as an example. This enables easy visual observation to check whether the laser beam L1 is applied on the upper focal point p.

If the irradiation position is dislocated, the irradiation position is adjusted by operating the slow-motion stage 9, the elevation adjusting knob 12, or the like. By this operation, a dislocation of the light receiver 3 serving as a sun tracking device can be corrected.

Then, as shown in FIG. 5A and FIG. 5B, the elevating device 24 and the turning device 25 of the heliostat 20 are adjusted so that the reflected light L4, which is a reflected light of the laser beam L2 applied on the facets 21 disposed on the heliostat 20, can enter the light receiver 3. By this operation, so-called origin alignment of the heliostat 20 is completed; therefore, the direction of the facet 21 is corrected.

As described above, the sun tracking sensor (the light receiving device 3) and the facet 21 can be corrected on site while carrying out actual measurement. Thus, correction at an extremely high accuracy can be achieved in comparison with correction carried out on the basis of workers' sense based on visual observation and of measurement.

Also, since the laser irradiation device 2 can be attached and detached, multiple heliostats 20 can be adjusted sequentially with the single irradiation device 2. Therefore, installation costs of the irradiation device 2 can be reduced.

Furthermore, since the correction operation can be carried out even by one person, the efficiency can be improved significantly compared to the case where adjustment is carried out by multiple persons on the basis of their sense upon spending time.

Incidentally, the solar thermal power generation system in the present embodiment is a beam-down system for solar thermal power generation. However, the correcting apparatus according to the present invention may be applied to a solar thermal power tower system as well.

In other words, the correcting apparatus according to the present invention may be used for any other system than a solar thermal power generation system as far as such a system is configured to collect solar heat into a predetermined position by means of reflecting mirrors of multiple heliostats or the like.

EXPLANATION OF REFERENCE NUMERALS

A solar thermal power generation system

1 correcting apparatus

2 laser irradiation device

3 light receiving device

20 heliostat

21 facet

24 elevating device

25 turning device

30 center reflector

33 receiver (heat receiving part)

c light path

p upper focal point

L1, L2 irradiated laser beams

L4 reflected light of laser beam 

1. A method for correcting a heliostat in a heat collecting device including: a center reflector provided in an upper portion thereof; a heat receiving part provided in a lower part thereof; and a plurality of heliostats arranged around the center reflector, the method for correcting a heliostat characterized by comprising the steps of: providing an irradiation device irradiating an upper focal point of the center reflector and the heliostat with laser beams, respectively; and adjusting an elevation angle and/or a turning angle of the heliostat so that a reflected light of the laser beam applied on the heliostat forms a same axial line as the laser beam applied on the upper focal point of the center reflector.
 2. An apparatus for correcting a heliostat in a heat collecting device including: a center reflector provided in an upper portion thereof; a heat receiving part provided in a lower part thereof; and a plurality of heliostats arranged around the center reflector, the apparatus for correcting a heliostat characterized by comprising an irradiation device irradiating the center reflector and the heliostat with laser beams, respectively, the irradiation device being provided on a light path connecting an upper focal point of the center reflector and the heliostat to each other.
 3. The apparatus for correcting a heliostat according to claim 2, characterized by comprising: a light receiving device detecting a reflection laser beam reflected from the heliostat, the light receiving device being provided in the vicinity of the laser irradiation device side-by-side therewith; and an adjusting device which turns and elevates the irradiation device and the light receiving device.
 4. The apparatus for correcting a heliostat according to claim 2, characterized in that the laser irradiation device is attached to and detached from the correcting apparatus by attachment and detachment means, and is driven by a storage battery.
 5. The apparatus for correcting a heliostat according to claim 2, characterized in that the laser irradiation device irradiates the upper focal point of the center reflector with a laser beam having a wavelength in a range of 500 nanometers to 590 nanometers.
 6. The apparatus for correcting a heliostat according to claim 3, characterized in that the light receiving device is a sun tracking device. 